A well-known test devised by psychologist Walter Mischel, together with Frances Mischel, and first administered to children of South East Asian Trinidadians and Afro-Trinidadians in the 1950s, that aims to measure the ability of children to delay or defer gratification (a skill involving impulse control, or what I sometimes refer to as “discipline”). The test came to be called the “Marshmallow Test” because in subsequent experiments, here in the United States, children were given the candy, marshmallows. The basic strategy of the test involved presenting young children (average ages about four years) with a single marshmallow each and being told that if they did not eat it right away they could have two marshmallows after about ten minutes.
The original experiment, incidentally, concluded that the presence or absence of a father in the home (a variable that itself was correlated with ethnicity) had a measurable difference on how well the children performed on the test. But why perform this test in the first place? Because there appeared to be strong evidence that those children who had developed a strong impulse control, in other words had the ability to defer gratification, went on to do better in school and in life generally than those with a weak impulse control.[1][2]
[1] Note: There are a number of videos available on the internet that show this experiment; please access them and after viewing them think how you would perform on a such a test if an adult version was available (e.g. a promise of $100 right now or $200 if you wait a year).
[2]. Subsequent studies (e.g., by Sperber, et al., 2024) found that performance on the test did not reliably predict what the original test attempted to predict (in terms of life chances).